> Ubuntu also does not even list a single mitigation strategy...

I installed newest Ubuntu mainline kernel, it did work for me:

https://kernel.ubuntu.com/mainline/v7.3.1/

I also did patch my FLOSS Go software:

https://github.com/wekan/wekan/commit/e9751b65d4

I'm maintainer of WeKan FLOSS kanban https://wekan.fi , https://github.com/wekan/wekan , and maintainer of FerretDB v1 fork https://github.com/wekan/FerretDB . There is also WeKan Snap package https://snapcraft.io/wekan/ .

But I don't work for Ubuntu, I don't have any answers why Ubuntu does not do something.